TRANSACTIONS OF SECTION G. 869 



The canal will loe of greater tottom width than the Suez, Amsterdam, or any 

 other ship canal, and it will absorb the whole of the waters of the rivers Mersey 

 and Irwell and their tributaries between Manchester and Warrinp;ton. 



From Eastham to Warrington, a distance of twenty miles, the tidal water of 

 the Mersey estuary will be impounded on one level by large entrance locks at 

 Eastham. 



The depth of the water in the canal will vary with the height of the tide, but 

 ■will never be less than twenty-six feet. The minimum bottom width of the canal 

 will be 120 feet, or nearly forty feet more than the Suez Canal. 



Above Warrington large ship locks will be constructed at Latchford, Irlam, and 

 liarton to raise the canal to the level of Manchester. The total length of the canal 

 will be thirty-five and a half miles. 



Docks, quays, and basins will be constructed at Mancbester, Barton, Warring- 

 ton. Partington, and Weston Point. 



The existing docks at Runcorn (now the property of the Manchester Ship 

 Canal Co.) are connected with the slap canal, and will afford the means of develop- 

 ing the trade of Staffordshire and the Potteries. 

 ' The docks at Weston Point and Ellesmere Port are on the ship canal. 



The Bridgwater canals recently purchased by the Ship Canal Co. are in con- 

 nection with the proposed new docks at Manchester, and all the inland canals are 

 in direct communication with the Bridgwater Canal, which will also join the ship 

 canal at Runcorn and Barton. 



A model of the canal was exhibited, and reference was made to a larger model 

 on view at the Manchester Jubilee Exhibition. 



4. Experiments on the Mechanical Equivalent of Seat on a large scale. 

 Bi/ E. A. CowPEB and W. Anderson. — See Reports, p. 662. 



6. What is a Drought ? ' By G. J. Symons, E.B.S. 



After referring to the difficulties he experienced more than twenty years ago in 

 arriving at a definition of a ' rainy day,' and, at a later period, in regard to 

 drought, the author stated that in 1880 he adopted a classification in regard to 

 droughts which has been generally used up to the present time : it is as follows : — 



Absolute droughts. — Periods of fourteen or more consecutive days absolutely 

 without rain. . 



Partial droughts.— TeTiods of twenty-eight or more consecutive days in which 

 the total rainfall does not exceed 0-115 inch. 



These definitions include the two elements of quantity of rain and of duration, 

 and neither opinion nor imagination can affect them. They have, however, no 

 connection with or resemblance to that which engineers, who_ are familiar with 

 water-works construction, consider as a drought. And the object of this paper is 

 tf) try and find a common ground whereby the records of the nearly three thousand 

 observers of rainfall in the British Isles may be utilised in the form most useful to 

 engineers. 



Among water engineers, however, droughts of 140, 160, 200, and even 240 

 days are recognised. It is quite certain that these are not ' absolute ' nor even 

 ' partial ' droughts, according to the definition that we have laid down, because 

 even in a dry place like London a register for thirty years gives no ' absolute ' drought 

 of more than twenty-eight days, nor ' partial ' drought of more tban forty-one 

 days. It is therefore evident that the drought of the engineer is something much 

 less severe than even my ' partial ' drought. 



The author then discusses this discrepancy, and concludes with a suggestion 

 wliich might meet the requirements of engineers ; at any rate, it will afford some- 

 thing to criticise. 



Lonr/ droughts.— Peviods of not less than sixty days with a total rainfall of less 

 than 2-00 in. 



' Mtmtlihj Mctem-ological Magazine, vol. xxii. (1887), p. 121. 



